The present invention relates to a filament for brushmaking, which has a specified cross section, is excellent in yield in stiffness, and in bend recovery, and when used in manufacturing paintbrushes, can give an excellent property profile such as paintability or paint pick-up.
Hitherto, hog bristles, goat hair and horse hair have been used as materials for brushmaking. Recently, synthetic filaments also have come into common in use as such materials. Brushes employing synthetic filaments have a number of advantages, such as stability or consistency in quality and supply, and therefor the demand and uses are expanding.
When used in manufacturing paintbrushes which are in great demand among brushes, synthetic filaments give brushes comparable in characteristic properties to brushes in which hog bristles are used. They are generally tapered or processed at their ends so that they can paint well, facilitate paint release and retain their stiffness during painting. They are currently available in basic cross section, such as circular, elliptic, triangular, Y-shaped, flat, cruciform, modified cruciform, three-leafed, four-leafed, cogwheel-shaped, circularly hollow and porously hollow. Among such conventional cross-sectional shapes, the rib type which has a plurality of projections is disadvantageous in that said projections engage one another to thereby make the filament crunching and disagreeable to the touch. Although the hollow filament is good in processability at its end, has small bulk density, and is of light weight, hence advantageous from the practical viewpoint, the hollow shapes are also disadvantageous in that once broken under a bending moment the filament cannot revert to its original shape for reasons of their cross-sectional structure, namely the periphery is welded completely, and in that since the filament is hollow, the paint which has entered the inside of the hollow filament at the end thereof can hardly come out.
It is an object of the present invention to provide a filament for brushmaking, which has a cross section capable of affording good yield, good processability, good bend recovery and good paint cleaning.
These and other objects of the present invention will become apparent from the description hereinafter.